MicroSquirt.com read only forum (Jan.15,2018)

After reading this post I swtiched from 1rst high, 2nd low to 1rst derivative, and ALL of my problems went away.

I had been having low rpm missfires, tach jumps, and detonation at boost onset around 3000 rpm even with drastically reduced timing. Changing the predictor algorithm fixed it all.

I think we definately need to play with this parameter more to find out what is ideal for different setups.

Ms2 V3 with a locked dizzy hall sensor.
I am going to switch to crank trigger.
I was using last interval but went to first derivative. With little worse of but I think I have excessive dizzy drive movement.

I am running MS2 V3.0 with a 36-1 VR combo. At the moment it's for fuel only.

I have an occasional stumble at idle and am running 1sr Deriv 2nd Low.

I will have a play with these and report back soon...

I have since again tried the other algorithms.

Last interval and 1st derivative seems to work fine.

1st High and 2nd derivative definitely results in poor idle.

OK, as far as I'm concerned MS-2 (2.35) DEFINITELY has only ONE predictor algorithm that really works : Last interval.

Since my previous post on this subject I've had my car on 1st Derivative as I thought that worked as well as LI (or better??), even at idle, and it does, UNTIL I SWITCH THE AC ON. That additional load somehow upsets the algorithm and results in really bad idle with much reduced RPM with unstable AFR. Opening throttle a tiny bit settled things down (this is where RPM based IAC could perhaps help) but I could not get my AFR at idle better than 13.

With Last interval, I've managed to get AFR up to 14 and ROCK STEADY. Idle RPM is also rock steady at 10BTDC and when the AC kicks in, Ive set my timing table so timing goes to 17BTDC (due to increase in MAP) and AFR is still steady at 14. Idle speed only drops by 50rpm or so

I switched mine to last interval, and it is better than first derivative, but first derivative appeared usable, 1rst high, 2nd low was not.